The current cannabis consumer no longer relies entirely on whole-flower consumption for their cannabis usage. When it comes to cannabis consumption, whether for medicinal or recreational purposes, the average user is aware of the medicinal and therapeutic benefits of cannabinoids and terpenes and demands conserved profiles, ease of use, accurate dose, and discretion. Most cannabis-related industries have set their sights on achieving these objectives.
Despite the fact that most phytocannabinoids have been effectively isolated and crystallized using very simple processes, similar techniques are ineffective when it comes to the elusive terpenes, which are distinguished by their distinct nature. As a result, the majority of market-available cannabinoids have terpene chemovars that are unique from those found in the parent plant.
THE DIFFICULTIES INTERFERING WITH TERPENE EXTRACTION
Cannabis producers have in the past modified conventional extraction procedures in order to extract terpenes from their plants. However, because of the significant loss of the chemicals and the high amount of contamination, the outputs were primarily terpene profiles that were only vaguely discernible.
Because of their distinct and highly volatile character, they have traditionally posed more difficulties in the extraction process than most cannabinoids. Because of their high heat susceptibility, terpenes require more assiduous approaches to isolate and extract than thick resins, heavy oils, alkaloids, and other substances that can be successfully extracted using relatively standard methods.
Nonetheless, some of these strategies have been shown to be more effective than others in the past.
Steam distillation and hydro-distillation are two types of distillation.
These two methods of terpene extraction have been in use for millennia and are considered to be among the more conventional ways of terpene extraction. During the process of steam distillation, lighter oils are solubilized in steam and condensed, allowing them to be collected. Hydro-distillation, on the other hand, is the process of directly immersing the stock material in boiling water until it becomes pure alcohol.
Nonetheless, both scenarios necessitate the use of extremely high temperatures and are therefore impractical for preserving original terpene profiles. It is common for highly volatile compounds to yield poor yields, which can be detrimental in the production of water-soluble compounds and, consequently, result in the development of hydrosols.
Extraction of Solvents
Another type of solvent extraction is hexane extraction, which uses hexane, CO2, or hydrocarbons as a solvent. Hexane and other water-insoluble solvents are the most cost-effective of the lot, but they are not recommended for use in food-grade extraction. Some terpenes have been shown to vaporize more quickly when exposed to certain chemicals.
CO2 extraction, which is quite similar to the normal extraction procedure, is extremely advantageous for food-safe terpene extraction. However, in contrast to these situations, terpene extraction is best when the CO2 is in the subcritical condition (see Figure 1).
The sub-critical state is characterized by lower temperatures and pressures than the supercritical state, respectively. Essential oils (small molecules with low molecular weight) are derived at their best in this state.
A subcritical run can be carried out with a supercritical-CO2 extractor by running the machine for a brief period of time and then stopping it.
Although this process can be used to extract dry flowers, it is primarily confined to dry flower extraction due to the possibility of acid formation due to the high moisture content of fresh flowers.
TERPENES ARE EXTRACTED USING CURRENT TECHNOLOGY IN THIS STUDY
Fortunately, technological growth has resulted in the development of novel methods for preserving and utilizing natural terpene profiles, which are now available. Different characteristics, such as polarity, volatility, and size, are considered while selecting a procedure, and these factors are subjected to proper judgment.
Among the various technologies that have been discovered and are still in development, a few have raced ahead of the rest, swiftly expanding and gaining acceptance within the cannabis niche:
Emission Capture and Retention
Terpenes are naturally occurring compounds released by plants. As a result, nature is combined with innovative science as the scale of this arrangement is increased. This was done in an experiment at the University of Kentucky’s Department of Pharmaceutical Sciences in Lexington, during which the terpenes were successfully removed from the resin and analyzed.
The scientists in charge of the experiment devised a set-up that included a live plant placed in a gas chamber with an air intake and a vacuum line that served as an air outlet for the plant from the chamber. The emitted gases, which included vaporized terpenes, were then passed through a pipette filled with tenax resin, which trapped the terpenes. After every 1-4 hours, the pipettes were replaced, and the terpenes were extracted from the resin with the help of a solvent.
When considering the positives, this method is typically considered to be cost-effective, efficient, simple to implement, and environmentally benign. The process can also be utilized to create food-grade terpenes with excellent profiles if it is carried out in accordance with industry standards.
On the negative, emission trapping is not a realistic choice for large-scale/commercial extraction due to the low emission effective ratio, which makes it impractical for such extraction.
Solid-phase microextraction is a technique for extracting small amounts of liquid from solids (SPME)
When using this procedure, the premise behind it is the simultaneous extraction and enrichment of desired analytes from a given matrix in a single step. There is little to no requirement for organic solvents or other time-consuming operations in this method, which is considered to be effective and efficient.
Terpenes are extracted from their matrix using a fiber-coated extractant, which extracts the desired chemicals from the matrix. While it is possible that further mechanical action will be necessary in some situations, the fundamental advantage of this approach is the fact that it uses mechanisms that are not dependent on a solvent.
In order to achieve the final isolates, the extracted terpenes present in the fiber material are placed in a gas chromatography chamber, which then extracts the terpenes from the fiber material and collects them for further analysis.
Also utilized in terpene analysis, both qualitative and quantitative, this method is more cost-effective and efficient than other methods in both the analysis and extraction stages.
Ultrasonic Extraction is a type of extraction that uses sound waves to extract materials.
It is worth noting that sonication is one of the most effective methods of creating high-yield terpenes. Through sonication, or the use of sound energy, researchers have discovered that terpenes such as -caryophyllene oxide and -pinene may be successfully extracted from plants.
A high mass transfer between the cell matrix and the solvent, which is typically a modest amount of ethanol, can be achieved through the use of ultrasound. As a result, due to its primary reliance on sound energy and little solvent use, it has a number of advantages, such as environmental safety, efficiency, ease of use, and health safety, among other things.
IMPORTING SCIENCE TO THE MARKET
A startup with a cannabis-related focus on botanical extraction, terpene and aroma compound research, AbstraxTM was founded in 2014. They claim to be able to generate unique, botanical, and non-cannabis-derived terpene formulations that are reminiscent of natural flower scents through the use of modern chemovar analysis and other new technologies. In a recent announcement, the company stated that their terpene products are now accessible on the Weedmaps Exchange for companies interested in purchasing natural terpenes for use in their product formulation.
While the industry has come a long way in terms of producing pure, full-spectrum terpene profiles, the total does not necessarily equal the sum of its parts, even when using procedures that claim to provide full-profile extracts. The research and development sector of the industry is therefore focused on developing laboratory-synthesised but basically organic terpene compositions that are profiled from terpenes derived from botanical sources.